Memory card

ABSTRACT

A memory card includes a memory cell, a connector, a controller, and firmware. The memory cell can switch between a plurality of states. The connector can be connected to an external device and exchange signals including commands and data with the external device. The controller exchanges signals with the connector, analyzes a received signal, and accesses the memory cell to record, retrieve or modify data based on the analysis result. The firmware is located within the controller, controls the operation of the controller, and can be set to a test mode or a user mode. When the firmware receives a test command from the external device and the firmware is set to the test mode, the firmware performs a defect test on the memory cell and transmits the result of the defect test to the external device through the connector.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of co-pending U.S.application Ser. No. 13/227,004 filed Sep. 7, 2011, which claimspriority to Korean Patent Application No. 10-2010-0110304 filed on Nov.8, 2010 in the Korean Intellectual Property Office, the disclosures ofwhich are each incorporated by reference herein in their entireties.

BACKGROUND

1. Technical Field

Embodiments of the present inventive concept relate to a memory card,and more particularly, to a memory card having a built-in self-test(BIST) function.

2. Discussion of Related Art

Due to advancements in the communication industry, large-capacity memorycards such as moviNAND are being made available to the general public.The moviNAND is an embedded NAND flash memory that uses a Secure Digital(SD)/MultiMediaCard (MMC) interface protocol. Large-capacity memory,such as a moviNAND, may include defects due to its high integrationdensity. Therefore, the entire region of the large-capacity memory mayneed to be tested to determine whether the memory is defective beforethe memory is shipped.

A device can be tested using a built-in self-test (BIST) circuit. TheBIST circuit includes a test vector that can test the device and acircuit that compares output values of the device. The BIST circuitidentifies whether a desired value is output from the device when thetest vector is input to the device as a test and outputs informationabout whether the device has passed or failed the test. A testing methodthat makes use of a BIST circuit uses a small number of pins and mayreduce testing costs. The BIST circuit may be used to test logiccircuits or memory cards.

As compared to a small-capacity memory card, a large-capacity memorycard may require a larger testing time, which can lead to increased testequipment investment costs and test processing times.

SUMMARY

At least one embodiment of the inventive concept provides a memory cardcapable of performing a built-in self-test (BIST) without requiringmodifications to an internal design thereof.

At least one embodiment of the inventive concept provides a memory cardin which BIST firmware is inserted into an embedded controller thereof.Thus, the memory card can test itself even if it is disconnected from anexternal device during the test.

According to an exemplary embodiment of the inventive concept, a memorycard includes a memory cell, a connector, a controller, and firmware.Data can be read from, written to, or deleted from the memory cell. Thememory cell can switch between a plurality of states. The connector canbe connected to an external device and exchange signals includingcommands and data with the external device. The controller exchangessignals with the connector, analyzes a received signal, and accesses thememory cell to record, retrieve or modify data based on the analysisresult. The firmware is located within the controller. The firmware maybe located within a memory region of the controller. The firmwarecontrols the operation of the controller, and can be set to a test modeor a user mode. When a test command is received by the firmware from theexternal device and the firmware is set to the test mode, the firmwareperforms a defect test on the memory cell and transmits the result ofthe defect test to the external device through the connector.

According to an exemplary embodiment of the inventive concept, a memorycard includes a memory cell, a connector, a controller, firmware, and apower supply. Data can be read from, written to, or deleted from thememory cell. The memory cell can switch between a plurality of states.The connector can be connected to an external device and exchangesignals including commands and data with the external device. Thecontroller exchanges signals with the connector, analyzes a receivedsignal, and accesses the memory cell to record, retrieve or modify databased on the analysis result. The firmware is located within thecontroller. The firmware may be located within a memory region of thecontroller. The controller controls the operation of the controller, andcan be set to a test mode or a user mode. The power supply enables thefirmware to maintain the test mode. When the firmware receives a testcommand once from the external device as a single signal when thefirmware is set to the test mode, the firmware performs a defect test onthe memory cell. During the test, the connector may be disconnected fromthe external device. However, power is still supplied from the powersupply to the memory card even when the connector is disconnected. Afterthe defect test, the firmware transmits the result of the defect test tothe external device through the connector.

According to an exemplary embodiment of the inventive concept, a memorycard includes a memory cell, a connector, a controller, firmware, and apower supply. Data can be read from, written to, or deleted from thememory cell. The memory cell can switch between a plurality of states.The connector can be connected to an external device and exchangesignals including commands and data with the external device. Thecontroller exchanges signals with the connector, analyzes a receivedsignal, and accesses the memory cell to record, retrieve or modify databased on the analysis result. The firmware is located within thecontroller. The firmware may be located within a memory region of thecontroller. The firmware controls the operation of the controller, andcan be set to a test mode or a user mode. The power supply enables thefirmware to maintain the test mode. The states include one or more of atransmission state, a data transmission state, a data reception state, abus test state, an idle state, a standby state, a disconnected state anda programming state. The firmware performs a defect test on the memorycell. During the test, the connector may be disconnected from theexternal device. However, power is still supplied from the power supplyto the memory card even when the connector is disconnected. The defecttest may be performed when a test command is received once from theexternal device as a single signal and the firmware is set to the testmode. After the defect test, the firmware transmits the result of thedefect test to the external device through the connector. The firmwareperforms the defect test by repeatedly switching the memory cell fromone of the states to another. The external device switches the firmwareto the user mode by recording drive firmware data of the memory card inthe memory region of the firmware and switches the firmware to the testmode by recording test firmware data of the memory card in the memoryregion of the firmware.

According to an exemplary embodiment of the inventive concept, a memorycard includes a wireless communication module, a controller, firmware,and a memory cell. The wireless communication module wirelesslyexchanges signals including commands and data with the external device.The controller exchanges signals with the module, analyzes a receivedsignal, and accesses the memory cell to record, retrieve or modify databased on a result of the analysis. The firmware is located within thecontroller. The firmware controls an operation of the controller. Thefirmware is configured to be set to a test mode or a user mode. When thefirmware receives a test command from the external device via the moduleand the firmware is set to the test mode, the firmware performs a defecttest on the memory cell and transmits a result of the defect test to theexternal device via the wireless communication module.

According to an exemplary embodiment of the inventive concept, a methodof configuring a memory card includes connecting an external device tothe memory card, the device sending a test command to a controller ofthe memory card to set firmware within the controller to a test mode,the firmware performing a test on a memory cell within the memory cardin response to the test command, the firmware transmitting a result ofthe test to the external device, and the external device sending anoperating command to the controller to set the firmware to a user modeonly when the result indicates the memory cell is free of defects. Themethod may further include the controller of the memory card determiningwhether a connection between a connector of the memory card and theexternal device has been terminated and a power supply of the memorycard maintaining a continuous supply of power to the firmware if theconnection has been terminated while the test is being performed.

According to an exemplary embodiment of the inventive concept, a memorycard includes a memory cell, a wireless communication module whichwirelessly exchanges signals including commands and data with anexternal device, a controller configured to exchange signals with themodule, analyze a received signal, and access the memory cell to record,retrieve or modify data based on a result of the analysis, and firmwarelocated within the controller. The firmware controls an operation of thecontroller and the firmware is configured to be set to a test mode or auser mode. When the firmware receives a test command from the externaldevice via the module and the firmware is set to the test mode, thefirmware performs a defect test on the memory cell and transmits aresult of the defect test to the external device via the wirelesscommunication module.

BRIEF DESCRIPTION OF THE DRAWINGS

The present inventive concept will become more apparent by describing indetail exemplary embodiments thereof with reference to the attacheddrawings, in which:

FIG. 1 illustrates a schematic configuration of a memory card accordingto an exemplary embodiment of the present inventive concept;

FIG. 2 schematically illustrates a built-in self-test (BIST) process ofthe memory card shown in FIG. 1 according to an exemplary embodiment ofthe present inventive concept;

FIG. 3 is a flowchart illustrating the BIST process of FIG. 2 accordingto an exemplary embodiment of the present inventive concept;

FIG. 4 is a flowchart illustrating a process of determining a testcommand in the BIST process of FIG. 3 according to an exemplaryembodiment of the present inventive concept;

FIG. 5 schematically illustrates a BIST process of a memory cardaccording to an exemplary embodiment of the present inventive concept;and

FIG. 6 illustrates state changes of a memory cell during the BISTprocess of FIG. 5 according to an exemplary embodiment of the presentinventive concept.

DETAILED DESCRIPTION

The present inventive concept will now be described more fullyhereinafter with reference to the accompanying drawings, in whichexemplary embodiments of the inventive concept are shown. The inventiveconcept may, however, be embodied in different forms and should not beconstrued as limited to the exemplary embodiments set forth herein. Thesame reference numbers indicate the same components throughout thespecification. In the attached figures, the thickness of layers andregions may be exaggerated for clarity. It will also be understood thatwhen a layer is refer edto as being “on” another layer or substrate, itcan be directly on the other layer or substrate, or intervening layersmay also be present.

As will be appreciated by one skilled in the art, aspects of the presentdisclosure may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present disclosure may take theform of an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present disclosure may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readablestorage medium. A computer readable storage medium may be, for example,but not limited to, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, apparatus, or device, or any suitablecombination of the foregoing. More specific examples (a non-exhaustivelist) of the computer readable storage medium would include thefollowing: an electrical connection having one or more wires, a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), an optical fiber, a portable compact disc read-onlymemory (CD-ROM), an optical storage device, a magnetic storage device,or any suitable combination of the foregoing. In the context of thisdocument, a computer readable storage medium may be any tangible mediumthat can contain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device. Program codeembodied on a computer readable medium may be transmitted using anyappropriate medium, including but not limited to wireless, wireline,optical fiber cable, RF, etc., or any suitable combination of theforegoing.

Hereinafter, a memory card according to at least one exemplaryembodiment of the present inventive concept will be described withreference to the attached drawings.

FIG. 1 illustrates the schematic configuration of a memory card 10according to an exemplary embodiment of the present inventive concept.FIG. 2 schematically illustrates a built-in self-test (BIST) process ofthe memory card 10 shown in FIG. 1 according to an exemplary embodimentof the inventive concept. FIG. 3 is a flowchart illustrating the BISTprocess of FIG. 2 according to an exemplary embodiment of the inventiveconcept. FIG. 4 is a flowchart illustrating a process of determining atest command in the BIST process of FIG. 3 according to an exemplaryembodiment of the inventive concept.

Referring to FIG. 1, the memory card 10 includes a memory cell 12, acontroller 11, and a connector 14. Data can be read from, written to, ordeleted from the memory cell 12 and the memory cell can switch between aplurality of states. The connector 14 can be used to connect the memorycard 10 to an external device 20 and exchange signals including commandsand data with the external device 20. The controller 11 can exchangesignals with the connector 14. The controller 11 can analyze a signalreceived across the connector 14 to access the memory cell 12 to record,retrieve or modify data based on the analysis result. The controllerincludes firmware 13, which may be located within a memory region of thecontroller. The firmware 13 controls the operation of the controller 11and can be set to a test mode or a user mode. When a test command isreceived from the external device 20 when the firmware 13 is set to thetest mode, the firmware 13 performs a defect test on the memory cell 12and transmits the result of the defect test to the external device 20through the connector 14.

The connector 14 may be directly connected to the external device 20 andserves as an input/output passage for data and commands. The connector14 may be a connection terminal made of a metal material. The connector14 may directly contact a port of the external device 20 to transmit orreceive a signal and/or data including a command. In an alternateembodiment, the connector 14 may be replaced with a wirelesscommunication module. As an example, the wireless communication modulecan transmit or receive data and commands using a short-range wirelesscommunication protocol or a wireless network. In at least oneembodiment, the wireless communication module is a near fieldcommunication (NFC) device. NFC is a set of short-range wirelesstechnologies, typically requiring a distance of 4 cm or less. Thewireless communication module may be an unexposed, embedded module ofthe memory card 10.

The controller 11 is embedded in the memory card 10 and controls theconnector 14 (or the wireless communication module) and the memory cell12. As compared to a controller that is separate from a memory card, anembedded controller used to control memory access may allow data to berecorded, retrieved, modified or deleted from memory spaces morerapidly. The controller 11 controls the process of recording externaldata or commands received through the connector 14 (or the wirelesscommunication module) in the memory cell 12. Also, the controller 11controls the process of retrieving, modifying or deleting data recordedin the memory cell 12. Accordingly, the controller 11 may improve theperformance of the memory card 10.

A firmware region (e.g., the firmware 13) is formed within thecontroller 11. The firmware 13 may be a core region of the controller11. The firmware 13 controls the controller 11 and serves as a platformthat facilitates the operation of the controller 11. As will bedescribed later, the firmware 13 according to the at least one exemplaryembodiment of the inventive concept may be set to the user mode when thememory card 10 is used to store and carry data. The firmware 13 may beset to the test mode to perform a defect test on the memory card 10 justbefore the memory card 10 is shipped as a complete product. The firmware13 being set to the test mode will be described in greater detail below.

The memory cell 12 is a region in which data may read from, written to,or deleted from. The memory cell 12 may be a collection of a pluralityof unit memory cells. The capacity and type of the memory card 10 may bedetermined by the memory cell 12. The memory cell 12 may store datainput from an external source, for example, multimedia files (such asway, mp3, tiff and avi) and text files (such as txt, doc and hwp). Inresponse to a query command from the external device 20, the memory cell12 may transmit a stored file to the external device 20 or transmitquery results to the external device 20. In addition, regions of thememory cell 12 can be freely recorded and erased. Therefore, differentdata values can be input to the same address by repeating a recordoperation a plurality of times. The external device 20 may be a digitaldevice in which the memory card 10 according to an exemplary embodimentof the inventive concept is used. Examples of the digital device includea personal computer (PC), a digital camera, an mp3 player, a camcorder,etc. For example, the memory card 10 may be connected to a digitaldevice such as those mentioned above and exchange data and signals withthe digital device, thereby increasing the scalability of the digitaldevice.

To retrieve, record, or delete data, the memory cell 12 may need toswitch from one of a plurality of states to another state. For example,when no external command is input, the memory cell 12 may remain in anidle state or a standby state. When a query command is received from theexternal device 20 (e.g., the digital device), the memory cell 12retrieves data based on query conditions included in the query command.Then, the memory cell 12 switches to a data transmission state andtransmits the retrieved data to the external device 20. The states ofthe memory cell 12 may include one or more of a transmission state, adata transmission state, a data reception state, a bus test state, anidle state, a standby state, a disconnected state, and a programmingstate. As will be described below, the firmware 13 may perform a defecttest on the memory cell 12 by repeatedly switching the memory cell 12from one of the states to another. The state changes of the memory cell12 for a defect test according to exemplary embodiments of the presentinventive concept will be described in detail below with reference toFIGS. 5 and 6.

The memory cell 12 in a controller-embedded large-capacity memory card(such as an embedded MultiMediaCard (eMMC) or a moviNAND memory) ishighly integrated. Since large-capacity memories may have more defectsthan small-capacity memories, the memory cell 12 may need to be testedfor errors or defects. While various testing methods can be used, in anexemplary embodiment of the inventive concept, a BIST method is used.The BIST method allows a test region embedded in a device to be used totest the device. Thus, test results can be obtained rapidly without theneed to modify the device.

Referring to FIGS. 2 and 3, the memory card 10 according to an exemplaryembodiment of the inventive concept includes the firmware region (e.g.,the firmware 13) within the controller 11, as described above. Thefirmware 13 may be set to one of the user mode and the test mode by theexternal device 20.

When the firmware 13 is set to the test mode, the external device 20 mayserve as a test hosting device for the testing of the memory card 10.The test hosting device transmits a test command to the memory card 10so that the memory card 10 performs a BIST. The test hosting device maybe installed on a production line as part of an inline process formemory production. The test hosting receives the test result from thememory card 10 and determines whether to ship the memory card 10 basedon the received test result. Alternately, when the firmware 13 is set tothe user mode, the external device 20 may be one of the digital devicesdescribed above.

The memory card 10 can be shipped as a finished product after a memorytest process determines that the memory card 10 is not defective.

The external device 20 connected to the memory card 10 according to anexemplary embodiment of the inventive concept records test firmwaredata, which is used to test the memory card 10, in the memory region ofthe firmware 13 within the controller 11, thereby switching the firmware13 to the test mode (operation S11). The test firmware data includes analgorithm for testing the memory card 10. The test firmware data mayvary according to a memory type of the memory cell 12 and/or acontroller type of the controller 11. When the algorithm is executed inresponse to a test command from the external device 20, the BIST may beimplemented.

The BIST begins when the external device 20 (e.g., the test hostingdevice) transmits a test command TCMD to the firmware 13, which is setto the test mode (operation S12). The test command TCMD may be receivedonce from the external device 20 as a single signal. The memory card 10according to an exemplary embodiment of the inventive concept may bedisconnected from the external device 20 after receiving the testcommand TCMD, which is used for the memory test. In the memory card 10according to an exemplary embodiment of the inventive concept, the testfirmware data including the algorithm for testing the memory card 10 isrecorded in the memory region of the firmware 13 within the embeddedcontroller 11. In addition, the received test command TCMD may includeinformation such as the test region, test time, and test pattern of thememory card 10. Therefore, even when the memory card 10 is disconnectedfrom the external device 20, the firmware 13 can repeatedly perform readand write tests by changing the state of the memory cell 12 anddetermine whether the memory card 10 is defective (operation S13).

After transmitting the test command TCMD, the external device 20 can beconnected to another memory card and transmit the test command TCMD tothe memory card while the memory card 10 performs the BIST. Alternately,instead of the external device 20 transmitting the test command TCMD toanother memory card, resources of the external device 20 can be appliedto another job while the memory card 10 performs the BIST. For example,while the memory card 10 performs the BIST, the connector 14 of thememory card 10 may be disconnected from the external device 20 afterreceiving the test command TCMD. Power may be supplied to the memorycard 10 to enable the firmware 13 to maintain the test mode regardlessof whether the connector 14 is connected to the external device 20. Inat least one embodiment, while the memory card 10 is tested, it does notexchange signals or data with the external device 20. However, eventhough the memory card does not exchange signals or data with theexternal device, in at least one embodiment, power is continuouslysupplied to the memory card 10 to enable the firmware 13 to continue itstest. In at least one embodiment, a power supply is provided to supplypower that enables the memory card 10 including the firmware 13 tocontinue its test.

The memory card 10 according to at least one exemplary embodiment canperform the BIST as long as power is supplied thereto. Since theexternal device 20 does not need to be continuously connected to thememory card 10, it can successively perform defect tests on other memorycards within a short time. This may increase the number of testsperformed per unit of time and improve test efficiency. Further,installation of additional test equipment for testing large-capacitymemory cards may not be necessary.

After the termination of the BIST, the firmware 13 may analyze theresult of the BIST (operation S14). In an alternate embodiment, thefirmware 13 does not analyze the result of the BIST and transmits theresult of the BIST to the external device 20 so that the external device20 can analyze the result of the BIST. To transmit the BIST result ofthe memory card 10 to the external device 20, the connector 14 of thememory card 10 is connected to the external device 20 and transmitsinformation about whether the memory cell 12 is defective to theexternal device 20 (operation S15). The result of the BIST may betransmitted once to the external device 20 as a single signal tominimize the connection time between the memory card 10 and the externaldevice 20, thereby shortening the processing time. The information maybe transmitted wirelessly to the external device 20 in an alternateembodiment where the connector 14 is replaced with the wirelesscommunication module.

Referring to FIG. 4, the test command TCMD transmitted from the externaldevice 20 (e.g., the test hosting device) to the memory card 10 isdetermined through a plurality of operations.

Information about the memory cell 12 to be tested is received from thememory card 10 (operation S21). If the same type of memory cardsproduced on successive production lines are to be tested, the aboveinformation may be received from a first memory card, and this operationmay be omitted when subsequent memory cards are tested.

Information about the memory card 10 (such as the capacity,specification, and pattern of the memory card 10) is analyzed (operationS22). The information received from the memory card 10 (e.g.,information about the capacity, specification, pattern or type of thememory card 10) is analyzed to test the entire region of the memory cell12 of the memory card 10. In an alternate embodiment, only part of thememory cell 12 is sampled and tested.

A region of the memory cell 12, which is to be tested is set based onthe analyzed information (operation S23), and a test time and a testpattern are determined (operation S24). When the entire region of thememory cell 12 is to be tested, it may be set as a test region, and thetest time and the test pattern may be determined in view of the size ofthe memory cell 12. In an alternate embodiment, when some regions of thememory cell 12 are to be tested, they may be set as test regions, andthe test time and the test pattern may be determined in view of the sizeof the selected test regions.

The test region(s) may include positions of a test start point and atest end point in the memory cell 12. The test pattern may include thesequence of a read test, a write test and a delete test performed by thefirmware 13 and the state change of the memory cell 12 according to theorder. For example, when the test pattern is set such that a read testof retrieving data from a memory region is conducted and then the dataof the memory region is modified, the memory cell 12 may switch from thestandby state to the transmission state and then to the datatransmission state to transmit data to the external device 20. Then, thememory cell 12 may switch to the data reception state to receive data tobe stored in a memory region and record the received data in the memoryregion. The test pattern may also include information about the sequenceof state changes of the memory cell 12.

When the test conditions have been determined, the test command TCMD isdetermined based on the test conditions (operation 25). The test commandTCMD may include information about the address, start point and endpoint of a memory region to be tested and information about the testtime and the test pattern. The determined test command TCMD istransmitted from the external device 20 to the firmware 13 via theconnector 14 (or the wireless communication module) of the memory card10. Here, the external device 20 is a host device which instructs thefirmware 13 to test the memory card 10 and appropriately process thememory card 10 based on the test result. The firmware 13 receiving thetest command TCMD analyzes a protocol of the test command TCMD andextracts the test conditions included in the test command TCMD.

As described above, after receiving the test command TCMD, the memorycard 10 according to an exemplary embodiment of the inventive conceptoperates independently of the external device 20, which requested thetests. For example, the test firmware data used to test the memory card10 has already been recorded on the firmware 13, and the test commandTCMD which determines test conditions has been input to the firmware 13.Therefore, even when the memory card 10 is disconnected from theexternal device 20, it can test itself. Further, in an embodiment of theinventive concept, the memory card requires power to continue performingthe tests. The external device 20, which requests the tests, maytransmit the test command TCMD to one memory card 10 and then may bedisconnected from the memory card 10. Then, the external device 20 maybe connected to another memory card and transmit the test command TCMDto that memory card. In this way, the external device 20 can test aplurality of memory cards 10 within a short time.

After the BIST of the memory card 10 is terminated, the memory card 10may be connected to the external device 20 to transmit the result of theBIST to the external device 20, which requested the tests. As describedabove, the result of the BIST of the memory card 10 may be transmittedonce to the external device 20 as a single signal. Then, the memory card10 may be disconnected from the external device 20.

When the result of the BIST indicates that the memory card 10 is notdefective, the external device 20 can switch the firmware 13 of thememory card 10 to the user mode so that the memory card 10 can beshipped as a finished product. For example, to allow the memory card 10to be used in a digital device such as a PC, the external device 20 canswitch the firmware 13 of the memory card 10 from the test mode to theuser mode by recording firmware data for driving the memory card 10 inthe memory region of the firmware 13. Since the firmware 13 can beswitched between the test mode and the user mode by changing the data inthe memory region of the firmware 13 without modifying the internalcircuit of the memory card 10 (as a finished product) according to anexemplary embodiment of the inventive concept, the BIST can be performedwith excellent efficiency.

Hereinafter, a memory card according to an exemplary embodiment of thepresent invention will be described with reference to FIGS. 5 and 6.FIG. 5 schematically illustrates a BIST process of a memory cardaccording to an exemplary embodiment of the present inventive concept.FIG. 6 illustrates state changes of a memory cell during the BISTprocess of FIG. 5 according to an exemplary embodiment of the inventiveconcept.

A memory card according to an exemplary embodiment of the inventiveconcept includes a memory cell, a connector, a controller, and powersupply. The controller includes firmware. Data can be written to, readfrom, or deleted from the memory cell. The memory cell is configured toswitch between a plurality of states. The controller may store thesestates. The connector can be connected to an external device andexchange signals including commands and data with the external device.The controller exchanges signals with the connector, analyzes a receivedsignal and accesses the memory cell to record, retrieve or modify databased on the analysis result. The firmware, which may be a memory regionlocated within the controller, controls the operation of the controllerand can be set to a test mode or a user mode. The power supply enablesthe firmware to maintain the test mode. When a test command is receivedfrom the external device when the firmware is set to the test mode, thefirmware performs a defect test on the memory cell. The test command maybe received only once as a single signal. During the defect test on thememory cell, the connector may be disconnected from the external device.However, even if the connector is disconnected, power is still suppliedfrom the power supply to the memory card. After the defect test, thefirmware transmits the result of the defect test to the external devicethrough the connector. If the connector had been disconnected from theexternal device, the result can be transmitted to the external deviceupon re-connecting the connector to the external device. When theconnector is replaced with a wireless communication module, the resultcan be sent upon a wireless connection being re-established.

Referring to FIG. 5, for a BIST of a memory card 10, a firmware 13 ofthe memory card 10 according to an exemplary embodiment of the inventiveconcept switches to the test mode and receives a test command TCMD froman external device 20. As described above in at least one of theprevious exemplary embodiments, the test command TCMD may includevarious information and conditions for testing the memory card 10. Basedon the test command TCMD, the firmware 13 conducts read, write, deleteand modify tests.

In FIG. 6, the state changes of the memory cell 12 during a test areshown. When no command is received from the firmware 13, a memory cell12 remains in a standby state S100 or an idle state S200, doing nothing.When the firmware 13 receives the test command TCMD from the externaldevice 20, the state of the memory cell 12 may be changed to performtests such as the read, write, delete and modify tests.

For the read test of the memory card 10, the firmware 13 switches thememory cell 12 to a transmission state S300 by transmitting a switch totransmission state command to the memory cell 12. Accordingly, data isretrieved from a requested memory region. Then, the firmware 13 switchesthe memory cell 12 to a data transmission state S400 by transmitting aswitch to data transmission state command to the memory cell 12. Aftertransmitting the data, the memory cell 12 switches to a disconnectedstate S600 to terminate the read test.

For the write test of the memory card 10, the firmware 13 switches thememory cell 12 to the transmission state S300 by transmitting the switchto transmission state command to the memory cell 12. Then, the firmware13 switches the memory cell 12 to a data reception state S500 bytransmitting a switch to data reception state command to the memory cell12. When the memory cell 12 is in the data reception state S500, data tobe recorded on the memory cell 12 is received. After the received datais recorded on the memory cell 12, the memory cell 12 switches to thedisconnected state S600 to terminate the write test.

In this way, the firmware 13 according to an exemplary embodiment of theinventive concept performs a defect test by repeatedly switching thememory cell 12 from one of a plurality of states to another. Althoughthe memory card 10 is disconnected from the external device 20 (i.e.,the test hosting device) during the defect test, it can still testitself, and, after the test, only the test result is transmitted to theexternal device 20. Based on the test result indicating whether thememory card 10 is defective, it is determined whether to discard or shipthe memory card 10.

The memory card 10 according to an exemplary embodiment of the inventiveconcept may further include a power supply (not shown), which enablesthe firmware 13 to maintain the test mode. The power supply may supplypower needed to test the memory card 10 from outside the memory card 10.After the memory card 10 is tested, if it is determined that the memorycard 10 is not defective, the firmware 13 switches to the user mode toterminate the test.

A memory card 10 according to at least one embodiment of the inventiveconcept is capable of performing a BIST without requiring modificationsto its internal design. Since the BIST firmware 13 is located within orinserted into the embedded controller 11 of the memory card 10, thememory card 10 can test itself even if it is disconnected from theexternal device 20 during the test. Test efficiency may be increased andcosts may be reduced when existing memory cards are replaced with thememory card 10.

Although the present inventive concept has been described in connectionwith exemplary embodiments thereof, those skilled in the art willappreciate that various modifications can be made to these embodimentswithout substantially departing from the principles of the disclosure.

What is claimed is:
 1. A memory card comprising: a memory cell; awireless communication module which wirelessly exchanges signalsincluding commands and data with an external device; a controllerconfigured to exchange signals with the module, analyze a receivedsignal, and access the memory cell to record, retrieve or modify databased on a result of the analysis; and firmware located within thecontroller, wherein the firmware controls an operation of thecontroller, and wherein the firmware is configured to be set to a testmode or a user mode, wherein when the firmware receives a test commandfrom the external device via the module and the firmware is set to thetest mode, the firmware performs a defect test on the memory cell andtransmits a result of the defect test to the external device via thewireless communication module.
 2. The memory card of claim 1, whereinthe memory card includes a power supply that supplies power to thefirmware.
 3. The memory card of claim 1, wherein the memory cell isconfigured to switch between a plurality of operating states and thestates comprise at least two distinct states from among a transmissionstate, a data transmission state, a data reception state, a bus teststate, an idle state, a standby state, a disconnected state, and aprogramming state.
 4. The memory card of claim 3, wherein the firmwareperforms the defect test by repeatedly switching the memory cell fromone of the states to another.